The OGMA 2'' Zero Light Leak Filter Holder allows you to use a 2 inch filter within your astrophotography imaging train. While many filter drawers have been designed for convenience, this filter holder has been designed to prevent the entry and dissemination of stray light into your imaging train. Modern astrophotography sensors are extremely sensitive to light. That's why a small light leak could ruin your entire night session of astrophotography. If you are often swapping filters, you should consider using a filter wheel, but if the same filter stays for hours inside your imaging train, then this is the filter holder for you.